Optically Interrogated Unique Object with Simulation Attack Prevention

A Unique Object (UNO) is a physical object with unique characteristics that can be measured externally. The usually analogue measurement can be converted into a digital representation - a fingerprint - which uniquely identifies the object. For practical applications it is necessary that measurements can be performed without the need of specialist equipment or complex measurement setup. Furthermore, a UNO should be able to defeat simulation attacks; an attacker may replace the UNO with a device or system that produces the expected measurement. Recently a novel type of UNOs based on Quantum Dots (QDs) and exhibiting unique photo-luminescence properties has been proposed. The uniqueness of these UNOs is based on quantum effects that can be interrogated using a light source and a camera. The so called Quantum Confinement UNO (QCUNO) responds uniquely to different light excitation levels which is exploited for simulation attack protection, as opposed to focusing on features too small to reproduce and therefore difficult to measure. In this paper we describe methods for extraction of fingerprints from the QCUNO. We evaluate our proposed methods using 46 UNOs in a controlled setup. Focus of the evaluation are entropy, error resilience and the ability to detect simulation attacks

Improving the longevity of optically-read quantum dot physical unclonable functions

Quantum dot physically unclonable functions (QD-PUFs) provide a promising solution to the issue of counterfeiting. When quantum dots are deposited on a surface to create a token, they form a unique pattern that is unlikely to ever be reproduced in another token that is manufactured using the same process. It would also be an extreme engineering challenge to deterministically place quantum dots to create a forgery of a specific device. The degradation of the optical response of quantum dots over time, however, places a limitation on their practical usefulness. Here we report methods to minimise the degradation of photoluminescence (PL) from InP/ZnS quantum dots suspended in a polymer and demonstrates reliable authentication using a fingerprinting technique to extract a signature from PL, even after significant degradation has occurred. Using these techniques, it was found that the addition of a polylauryl methacrylate (PLMA) copolymer improved the longevity of devices. The best performing example of this was the Polystyrene-PLMA based material. From this, it is projected that 1,000 bits of information could be extracted and read after a period of years, therefore providing a compelling solution to the issue of counterfeiting

Coupling Scanning Electrochemical Microscopy and 3D Modelling to Probe Membrane Permeability of Human Bladder Cancer (T24) Cells

Scanning electrochemical microscopy (SECM) scans a biased ultramicroelectrode (≤ 25 µm) probe over a sample to characterize topography, physical properties and chemical reactivity. In this dissertation, SECM was used to investigate the metal-induced changes in membrane response of single live human bladder cancer cells (T24). SECM imaging was coupled to 3D finite element method (FEM) simulations which were the first of their kind, providing advanced quantification of sample traits under conditions not previously usable. The effects of Cd2+ on T24 cell membrane permeability were examined. Experimental depth-scan imaging was coupled with full 3D FEM simulations, eliminating many limitations of previous 2D-axially symmetric models. Hundreds of probe approach curves (PACs) can now be extracted from depth-images and theoretically fit to quantify membrane permeability at any location across the cell surface (Chapter 2). SECM was utilized to examine the membrane response of T24 cells following exposure to toxic dichromate (Cr(VI)). Two electrochemical mediators were examined, the membrane permeable ferrocenemethanol (FcCH2OH) and impermeable ferrocenecarboxylate (FcCOO‑). Cr(VI) induced permeability change was observed with both mediators and compared (Chapter 3). Chronic Cr(VI) induced cell stress, was then examined. Similar permeability curve shape was observed, with shifts in response time based on concentration of Cr(VI) stressor (Chapter 4). Trace essential metals such as Cr(III) are essential in low concentrations but toxic in high concentration. Membrane-response was investigated by SECM, using both FcCH2OH and FcCOO- redox mediators. Theoretical SECM depth-scans were produced using 3D FEM simulations, and used to quantify cell membrane permeability (Chapter 5). Complex close-proximity cell clusters were experimentally imaged by SECM 3D scanning mode. Tailored 3D model geometries were created, generating complimentary theoretical maps of the experimental cell clusters. The simulations were capable of providing a strong theoretical fit to the experimental results. Limits of cell proximity for SECM characterization were determined based on the probe size (Chapter 6). Nanoscale SECM imaging of single live cells were performed using a laser-pulled 130 nm radius Pt disk electrode. A tailored 3D model was created, from which cell topography was accurately characterized using membrane-impermeable Ru(NH3)63+, and cell membrane permeability was quantified with FcCH2OH (Chapter 7)

Aeronautical engineering: A continuing bibliography with indexes (supplement 279)

This bibliography lists 759 reports, articles, and other documents introduced into the NASA scientific and technical information system in May 1992. Subject coverage includes: design, construction, and testing of aircraft and aircraft engines; aircraft components, equipment, and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

Simulation and control engineering studies of NASA-Ames 40 foot by 80 foot/80 foot by 120 foot wind tunnels

The development and use of a digital computer simulation of the proposed wind tunnel facility is described. The feasibility of automatic control of wind tunnel airspeed and other parameters was examined. Specifications and implementation recommendations for a computer based automatic control and monitoring system are presented

Harnessing QD-PUFs for Secure Authentication via Fuzzy Fingerprint Generation

The field of security technology is an eternal race. For every step forwards that is made in producing technology to help secure something it is not long behind it that those who seek to attack it make one also. Cryptography is one key example, even as encryption algorithms get more advanced so too do the computers that can be used to brute force them. Anti-counterfeiting is another. For each new complex watermark or hologram to prove authenticity there shortly follows better production techniques that aid in replicating them. There is a solution to this within the concept of Quantum Dot Physically Unclonable Functions (QD-PUFs). Underpinned by the laws of quantum physics rather than mathematically hard problems they are, as their name suggests, impossible to replicate. Providing an extremely appealing solution to security concerns where authentication and identification are required. There are several matters however that prevent QD-PUFs from being used in a much more wide spread manner. The aim of this thesis is therefore to address these in order to move QD-PUFs closer to being widely available. The foremost of these issues is a way to digitise the output of QD-PUFs. This forms the bulk of this thesis in detailing, analysing and discussing the fingerprinting algorithms designed to perform this task. As well as this the stability of the QD-PUFs, how to hide the information within fingerprints and the influence of varying incident wavelengths are covered. All to provide a comprehensive discussion on QD-PUFs and their fingerprints

Night moves: A mise-en-scene of a luminous economy

Since the general electrification of ambient urban lighting in the late nineteenth century, complex arrangements of functional and aesthetic lighting have become increasingly deployed to intensify the capitalization of the city at night. Contemporary solid-state lighting integrated with networked control systems means that scenic effects once contained within theatrical and cinematic production, have infiltrated the built spaces that we occupy. As digital imaging technologies converge with the built environment, the city at night can be considered as a moving image. This research considers the implications of the nocturnal city when it is understood as a manufactured atmosphere, where the distinctions between media interfaces and the construction of urban space are no longer distinguishable as distinct zones of experience. By employing Bertolt Brecht’s and Antonin Artaud’s concepts of a mise-en-scene of light as a critical and transformational tool, the thesis develops connections between current theories of atmosphere and post-cinematic urbanism. The thesis proposes a practice-based analytical and critical mise-en-sce ne that draws on embodied empirical methods for creating lens, light and sound-based artworks within installation art and the urban environment. This research explores the effects of light and digital projection on urban subjectivity and its representations. Recent formulations of atmosphere in Gernot Böhme’s phenomenological conception of architectural atmospheres and Andreas Philippopoulos-Mihalopoulos’ theorisation of lawscape are integrated into a broader corpus of analysis and theory through empirical, theoretical and historical modes of enquiry. Together, the written thesis and body of practice provide the framework phototropia. This aims to establish a transversal platform for critical thought and practice from which to think and remake the city at night. From the perspective of a material practice this method offers ways of understanding the changing relations between imaging technologies and contemporary urban subjectivity

Development of multidimensional fluorescence imaging technology with a view towards the imaging of signalling at the immunological synapse

This thesis describes the development and application of multidimensional fluorescence imaging to signalling events at the Natural Killer cell immunological synapse. The primary techniques used in this work are intensity imaging, ratiometric spectral fluorescence imaging and fluorescence lifetime imaging, which have been applied to live and fixed cells. It is shown that although protein accumulation at the immunological synapse can simply be determined by intensity imaging, the presence of protein does not indicate that signalling events are occuring. Signalling at the inhibitory synapse as determined by KIR2DL1 receptor phosphorylation is imaged by means of confocal FLIM. The resolution achievable using this technique is then improved upon by the use of optical tweezers for cell reorientation. A comparison of the sectioning abilities of single point confocal and multiphoton microscopy with multipoint spinning disk based systems is made and a means of achieving an increased rate of imaging for the gold standard of FLIM methods, TCSPC FLIM, is proposed. The proposed multifocal multiphoton TCSPC FLIM system is first simulated and then implemented, with a comparison to widefield time-gated FLIM being carried out. The system is then used to image test samples, and to acquire cell-level metabolic information with the highest time resolution achieved to date via autofluorescence imaging of NADH. Membrane order at activating and inhibitory NK cell immunological synapses is examined by means of ratiometric imaging of a lipid phase-sensitive dye, and software is developed for the analysis of NK cell spreading patterns, and this software was used to demonstrate that the spreading behaviour of NK cells is affected by the type ofligands encountered in terms of the symmetry and dynamics of spreading